View Full Version : n00b trying Combustion

06 June 2003, 02:32 AM
Hello, I'm ANOTHER n00b trying to get a handle on the Combustion 2.1 demo and I am having some issues with it.. :annoyed: I would really appreciate it if anyone could tell me if I'm doing something wrong (causing it to be slower) or if my video card or something is just not playing nicely..

Anyway, the biggest issue I'm having is that it's SO FREAKIN SLOW!? I've got Dual Athlon MP2000+ and 1GB of RAM, an ATI Radeon 9700 Pro (OpenGL issues??) and a few hard drives.

I know Combustion isn't a video editing program, but what I'm trying to do is add some effects to video clips. So, here's what I do: I run Combustion. Open (1) 30 second video clip (720x480 MiniDV) into the workspace. I get less than 5 fps playback without any operations or anything done to the clip. So, I try rendering a few seconds to RAM that I want to work on (adding text with a few effects like movement & opacity). It takes 5-10 minutes to render maybe 100-150 frames to RAM at half resolution, medium quality.

The next issue I'm having is the audio. I'm just trying to synch the text and some effects to the audio track of the video clip. I go to a later point in the clip (17seconds) and render a few seconds to RAM, but the audio that it plays back is from the begining of the entire clip, not the audio of that segment of video.

I also have my Cache set to use about 80% of my RAM (1gb) and I've never seen its usage go above 100mb even after rendering to RAM. Is there some big stupid thing that I'm missing?!? Does C*2 hate my video card? Any suggestions???? I really want to learn C*2 and maybe even purchas Combustion 3 when it comes out, but C*2 just performs SO badly on my computer..

06 June 2003, 01:19 AM
In the preference check if the Software Opengl is unchecked. You'll see more performances.


06 June 2003, 09:07 AM

I see a few things I can highlight for you here which may clarify the way combustion works....

Firstly, hardware is essential for the speed of the software. The faster the processors, the better the performance. Combustion can load and calculate at a faster rate. The display card plays an essential part in the particles. There are certified cards that we know work with combustion. You can see this list at

As for the RAM. This dicates how many frames you can playback in realtime. With only one gig, you will NOT be able to playback an entire 30 second clip in real-time. The software was not designed that way. Everything needs to be loaded into memory before it plays back in realtime. When you press play, combustion will load what ever is in the timeline. IF there is more video in the composite then the ram can handle and you have not limited the play area to a smaller region combustion will keep trying to load the entire clip. When the RAM gets full it will start recycling the RAM and you will only ever have the 5 fps.

To maximise the usage of the RAM and increase performance you can do a few things.

Firstly you can drop the quality of the images while working with them. ON the right of the interface you will see a button that says "Best"/"Preview"/"Medium"/"Draft". Try working at "Preview" to start. To speed it up even more then drop to a lower resolution.

Secondly, Limit the area where you are working. If you are only working with the middle 5 seconds of the clip there is no reason to load the entire 30 second clip into the RAM. This can easily be done. Just below the Scrub bar you will see a small green and red dot. The green dot represents your start point and the red dot indicates you end point. These can be moved with either the mouse or using SHFT-I for in and SHFT-O for out. When you play the composite, combustion will only cache the area within the markers and this make make better usage of your RAM. Once combustion has scanned all those frames once you should then get full frame playback.

Audio. Combustion loads the audio into the RAM with the video to get playback but there is a certain order in the way it works. Combustion first loads the video into the RAM and then the audio. However if the video takes up all the available RAM, then the audio either will not play or cut out half way. This is another reason for not loading all the video frames because of a lack of memory.

As for syncing the audio, when you load you clip into combustion you will see an option that says "Link to...". You click on this option and this will lock your audio to whatever you tell it to. In this case you will lock you audio to your imported layer. Once this is done you should not have the audio problem anymore.

As for the RAM cache only using less then 100 megs when working. I find this a bit strange. I've seen this happen when there are other applications running in the background. Combustion can only use the memory that is available and not any more. Try shutting down all your other applications and see if the performance improves.

I hope this helps.



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